The present invention relates to fluid conduit assemblies, and more particularly to hydraulic conduit assemblies for use with ram air turbines (RATs).
Modern aircraft often include a secondary or emergency power system that can provide power in the event that power is unavailable from a primary power system. RATs are commonly used for secondary or emergency power systems to provide electrical and/or hydraulic power. A typical RAT is deployable in flight by opening suitable doors or hatches in the aircraft's fuselage. The RAT presents a rotatable turbine to oncoming airflow, which rotates the turbine. Rotational energy (torque) from the turbine is then transmitted to a suitable power conversion device (e.g., generator, pump, etc.) that converts that rotational energy to a desired form for use by the aircraft. For RAT installations that include a hydraulic pump for moving hydraulic fluid, suitable fluidic conduits must be provided to deliver the hydraulic fluid to and from the pump.
RATs that include a hydraulic pump located on a deployable RAT module must be configured in such as way as to allow hydraulic fluid transmission from the RAT module to other desired locations while still permitting actuation of the RAT module between stowed and deployed positions. Such fluid transmission has been accomplished in the past using flexible hoses or a pivot tube assembly.
Prior art aircraft components have included transfer tubes for low pressure installations at internal locations, for providing a fluid conduit between two components that accept fluid. Some prior art low pressure transfer tubes 6, shown in FIG. 4, have had ends of unequal diameters having cylindrical ends with grooves for sealing o-rings. Other prior art low pressure transfer tubes 8, shown in FIG. 5, have included crowned (i.e., curved) ends without sealing rings or gaskets. These prior art transfer tubes have been used in internal locations where some fluid leakage may be acceptable. However, these prior art transfer tubes were not configured to handle high pressure applications, and permitted only a relatively low degree of misalignment between the components they connect, that is, between the connection interfaces at opposite ends of the transfer tubes. FIG. 6 shows a prior art RAT with external high and low pressure transfer tubes 9 with cylindrical ends having seals and a pressure bolt 9-1 passing through a spacer tube 9-2 that is shimmed using shims 9-3. In cross-section, the transfer tubes 9 generally resemble longer versions of the transfer tube 6 shown in FIG. 4.